A QUICK COOLING AIR CONDITIONING SYSTEM

Abstract: A quick cooling air conditioning system that preserves high pressure refrigerant, in a portion of the refrigerant path or in a dedicated reservoir (205), after the shutdown of the air conditioning compressor (201). The quick air cooling is achieved by the instant application of high pressure refrigerant to the evaporator (209) at the start-up of the air conditioning system.

Description: A QUICK COOLING AIR CONDITIONING SYSTEM FIELD OF THE INVENTION The present invention relates to refrigeration systems. More particularly, the present invention describes a means to provide a quick cooling effect. BACKGROUND OF THE INVENTION An air conditioning system cannot pump heat when the refrigerant is in the non-operating equilibrium. As used herein, a non-operating equilibrium state for the system is that state in which the high pressure side of the compressor is returned to a low pressure condition when the compressor is turned off. Assuming that all other factors remain the same, the closer the refrigerant in the system is to the operating equilibrium, the more efficient the heat pumping action. When the refrigerant in the system is at a non-operating equilibrium, the efficiency is zero, even though the compressor may be running. Heat pumping efficiency of the air conditioning system increases from zero as the refrigerant in the system reaches the operating equilibrium. Conventional systems allow the refrigerant to return to a non-operating equilibrium when the compressor is turned off. As a result, the air conditioning system has no heat pumping action the instant it is turned on. As stated above, once the compressor is turned on the efficiency of the air conditioning system starts to increase from zero as the refrigerant in the system reaches the operating equilibrium. This causes a delay from the time the system starts using energy to the time the system begins to cool. Other attempts to provide quick cooling of an automobile's interior have been attempted. One such product that can quickly cool down the internal temperature of an automobile, is a pressurized spray can. Apparently, the cooling effect is achieved by the depressurization and evaporation of the chemical in the spray can. The major disadvantage of the product is that it is not reusable and has possible environmental impacts. Therefore, the primary purpose of the present invention is to provide cooling action and to increase the heat pumping efficiency to a positive number the instant when the compressor of an air conditioning system is turned on. SUMMARY OF THE INVENTION According to this invention, the time to cool the interior of an automobile during the start-up can be shortened by the instant application of high pressure refrigerant to the evaporator at start-up of the air conditioning system. The high pressure refrigerant is supplied by a refrigerant reservoir, where the reservoir is an addition to the conventional air conditioning system. Alternatively, high pressure refrigerant can be stored in a component or components in the high pressure refrigerant path such as the accumulator and the refrigerant dryer, or a combination thereof. A scheme has been proposed by this invention to integrate the refrigerant reservoir with the conventional air conditioning system to make this quick air cooling possible. DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram showing a prior art air conditioning system. Figure 2 is a schematic diagram showing an air conditioning system, together with the modification proposed by this invention. Figures 3-20 are schematic diagrams showing additional alternative modifications of the air conditioning system shown in Figure 2. DETAILED DESCRIPTION OF THE INVENTION A conventional air conditioning system is depicted in Figure 1. The accumulator 105 is shown in two possible places; its placement is not important to the present invention. There may be other components in the system, such as refrigerant dryer and valves. They are not important to the basic principle of operation of the system and this invention. Therefore, they are not shown in any figure for clarity. There are generally two equilibrium states that the system may be in. The first equilibrium state is referred as the non-operating equilibrium. After a system has not been in operation for while, the refrigerant will have the same pressure, phase, and temperature throughout the system. The second equilibrium state is referred to as the operating equilibrium. Referring to Figure 1, when the system is in operating equilibrium, the following is a list of phase and pressure of the refrigerant in the system: A) Between compressor 101 and condenser 102: high pressure, vapor phase, high temperature. B) Between condenser 102 and expansion valve 103: high pressure, liquid phase, a medium temperature. C) Between expansion valve 103 and evaporator 104: low pressure, vapor phase, low temperature. D) Between evaporator 104 and compressor 101: low pressure, mixed vapor and liquid phase, medium temperature. It would be apparent to one skilled in the art that for a non-operating equilibrium system, when the compressor is first energized, no heat pumping action is accomplished. Furthermore, maximum heat pumping action is not achieved until the system reaches operating equilibrium. To reduce this inefficiency, the air conditioning system may be used to give out cool air immediately if high pressure liquid and/or vapor refrigerant is available between the condenser 102 and the expansion valve 103 at the beginning of the operation of the air conditioning system. The preferred embodiment is a modification of the conventional air conditioning system. The modification, as conceptually shown in Figure 2, consists of the addition of three valves (206-208) and a pressurized reservoir 205 for liquid refrigerant. A refrigerant accumulator, which is normally in the air conditioning system, is not shown in Figure 2 for clarification. However, it may be put in various locations as shown in Figure 1 (element 105) . Physically, the accumulator, the refrigerant dryer, and the reservoir may be combined into one unit depending on the actual design. Opening and closing of the valves shall be synchronized with the operation of the compressor as indicated by the dashed lines. Referring to Figure 2, the present invention consists of a compressor 201, condenser 202, expansion valve or similar devices 203, evaporator 204, refrigerant reservoir 205, upstream valve 206, downstream valve 207, and by-pass valve 208. Note that valve 208 allows the main system to return to a non-operating equilibrium state when the system is shut off, i.e., the high pressure side of the compressor is returned to a low pressure state when the compressor is turned off. In operation, compressor 201 is running, valves 206 and 207 are open, valve 208 is closed, and the other parts of the system will operate as in the conventional system. As the refrigerant is compressed by the compressor 201, it changes into a liquid at the condenser 202. As with the conventional system, the liquid refrigerant vaporizes as it passes through expansion valve 203 to the evaporator 204 before returning to the compressor. The air cooling is achieved by the heat absorption due to the vaporization of liquid refrigerant at the evaporator. When the compressor 201 is turned off, the valves 206 and 207 are closed, and valve 208 is opened. Thus, liquid refrigerant is trapped in the reservoir and stays in the liquid phase under ambient temperatures. Refrigerant in the rest of the system reaches the non-operating equilibrium state. When the compressor 201 is turned on again, valves 206 and 207 are opened, and valve 208 is closed. Liquid refrigerant in the reservoir 205 will flow through expansion valve 203 (or similar devices) to evaporator 204 to provide quick cooling at the instant when the air conditioner is turned on. The time for the refrigerant in the preferred embodiment to achieve the operating equilibrium after turned on is greatly reduced compared to the time required for the conventional air conditioning system. Thus, the preferred embodiment has a positive heat pumping efficiency at start up while the conventional air conditioning system has zero efficiency at start up. It may be necessary to delay the switching of valves 206 - 208 to allow the compressor to come up to speed first, thereby reducing start-up stress on compressor 201. Another possible solution, valve 206 could remain closed while valve 208 is closed and 207 is opened. This will keep the liquid refrigerant from back flowing into the compressor 201. The preferred embodiment provides several advantages to other quick cooling solutions. The preferred embodiment can be added to existing air-conditioning systems with minimal modification to the original air conditioning system. Reservoir 205 and valves 206-208 could all be manufactured into to a single component. Assuming that the accumulator (105 in FIG. 1) is between the condenser 102 and expansion valve 103, the single component can simply replace the accumulator. This quick cooling system requires a relatively simple control system. Basically, the system must only open valves 206 and 207, close valve 208, when compressor 201 is turned on; and close valves 206 and 207, open valve 208, when compressor 201 is turned off. Another advantage of the preferred embodiment is the minimal use of mechanical moving parts, hence high reliability. The three additional valves (206-208) will not reduce the overall reliability of the system by a significant amount. Generally, leaks and faulty compressors are the primary source of system failures. An increased failure rate for the compressor could be caused by allowing the high pressure liquid in the reservoir to back flow into the compressor during start-up of the compressor. This can be reduced by proper sequencing of the new valves as discussed above. Several modifications are possible to the preferred embodiment. These include: 1. Valve 208 could be a check valve or a small diameter tube like a capillary tube, in some arrangements such as the arrangement of Figure 2. 2. Valve 206 may be moved to a location between compressor 201 and condenser 202. Valve 208 has to be moved accordingly to provide the safety mechanism and allow the system to return to a non-operating equilibrium state during shutoff. For example, valve 208 may be connected between the high pressure side of compressor 201 and the inlet side of expansion valve 203. A system configuration employing this modification is shown in Figure 3. 3. Valve 207 may be moved to between evaporator 204 and expansion valve 203. Valve 208 then has to be moved accordingly to provide the safety mechanism. For example, valve 208 may be connected between the outlet of condenser 202 and the inlet of evaporator 204. This modification is shown in Figure 4. 4. Other control mechanisms for the valves are possible. For example, the system could open valves 206 and 207 and close valve 208 when the compressor 201 is turned on; then close valves 206 and 207 and open valve 208 when pressure at the reservoir reaches a certain pressure. To reduce start-up demand on the compressor, during the start-up period of the compressor, valve 206 could remain closed while valve 208 is closed and 207 is opened. 5. An adapted combination of modification 2 and 3 above. 6. Although it is not desirable for efficiency concerns, valve 206 may be a check valve. 7. The various valves of the system may be sequenced at start-up in order that the compressor 201 comes up to speed before the stored high pressure refrigerant is presented to the high pressure side of the compressor. Thus, either the valve (e.g. 206) that isolates the compressor from the condenser could be delayed in opening, or the bypass valve (e.g. 208) could be delayed in closing to achieve this desired result. The same principle can also be used for other refrigeration systems to reduce the time required to achieve refrigeration temperature. The principle can also be adapted to non-conventional air conditioning/refrigeration system, so long as their cooling rate can be improved by -li¬ the release of stored working medium during a start-up period. The three embodiments of Figures 2-4 have been explained in function as examples of how the present invention can be implemented. However, many variations of the components making up an air conditioning system are possible, all of which may employ the concepts of this invention. These variations result from the different placement of components of the basic air conditioning system and the components required to implement the improvement according to the present invention. For example, either high pressure vapor phase, high pressure liquid phase, or high pressure mixed liquid and vapor refrigerant can be isolated and maintained when the compressor is turned off. The expansion valve may or may not be included in the portion of the refrigerant path that is isolated. Similarly, the condenser may or may not be included in the portion of the refrigerant path that is isolated. The condenser may function as both the condenser and the reservoir and the reservoir could be eliminated. In a less preferred embodiment, one of the valve means, valve 206, could be eliminated altogether, in which case the compressor 201 (when off) acts as the upstream valve for isolating the high pressure refrigerant. Additionally, combinations of some of these variations are possible, and if a bypass valve 208 is used, it also has various possible connections in the system (as indicated by the dotted lines in the figures) and yet functions in the manner required as a pressure relief valve when the compressor 201 is turned off. Since it is rudimentary to one of ordinary skill in the art of air conditioning to readily understand the differences in operation of an air conditioning system in which the various components are variously placed. Figures 5-20 are presented for viewing different possibilities for interconnecting the components of an air conditioning system employing the present invention, and it is deemed unnecessary and unwarranted to explain each variation in detail. It is to be understood, however, that the accompanying drawings are not exhaustive as to the number of possible different configurations of an air conditioning system employing the present invention, and the embodiments shown and described herein are to be considered as exemplary. Of course, for any combination of components which results in two valves in series (such as the control valve 207 and expansion valve 203 in Figure 4) a single, dual-function valve can be substituted. In short, the present invention stores the vapor or liquid refrigerant produced by the system during operation in a reservoir or in the fluid conduits of the system, thereby keeping the stored refrigerant under pressure (in a vapor or liquid phase) when the compressor is turned off. To achieve quick cooling, the stored refrigerant is released instantly at start-up to the evaporator through the expansion valve when the compressor is turned on. Although the preferred embodiment of the invention has been illustrated, and that form described, it is readily apparent to those skilled in the art that various modifications may be made therein without departing from the spirit of the invention or from the scope of the appended claims.

Claims: AMENDED CLAIMS [ received by the International Bureau on 06 January 1995 (06.01.95); original claims 6-20 amended; new claims 21-38 added; other claims unchanged (7 pages)] evaporator means providing said cooling effect by allowing external heat to be absorbed into said refrigerant; and isolation valve means in said path for selectively isolating and maintaining high pressure refrigerant in a portion of said path, said isolation valve means operating to isolate and maintain high pressure refrigerant in said path portion responsive to said compressor means being turned off, and operating to release the isolation high pressure refrigerant responsive to said compressor means being turned on. 7. A refrigeration system for providing a cooling effect upon start-up, said refrigeration system having a closed loop fluid flow path for a refrigerant, said system comprising: a compressor means in said path for compressing a low pressure refrigerant into a high pressure refrigerant, said compressor means having a low pressure side and a high pressure side; a condenser means having an input and an output, said condenser means input coupled to said high pressure side of said compressor means, said condenser means allowing release of heat from said high pressure refrigerant; an expansion valve means having an input and an output, said expansion valve means input coupled to said condenser means output, said expansion valve means converting said high pressure refrigerant to said low pressure refrigerant by allowing said refrigerant to expand, wherein said expanding of said refrigerant reduces said refrigerant's temperature; an evaporator means coupled between said expansion valve means and said low pressure side of said compressor means, said evaporator means providing said cooling effect by allowing external heat to be absorbed into said refrigerant; isolation valve means in said path for isolating and maintaining said high pressure refrigerant in a portion of said path when said compressor means is turned off; and pressure relief valve means bypassing said isolation valve means, said pressure relief valve means being open when said compressor means is turned off, thereby allowing said isβlation valve means to maintain said high pressure refrigerant in said path portion and the remainder of said refrigeration system to reach a non-operating equilibrium state when said compressor means is turned off. 8. The refrigeration system as claimed in Claim 6, wherein said isolation valve means includes a first isolation valve in said path between said condenser means and said expansion valve means, and a second isolation valve in said path between said first isolation valve and said expansion valve means. 9. The refrigeration system as claimed in Claim 6, wherein said isolation valve means includes a first isolation valve in said path between said compressor means and said condenser means, and a second isolation valve in said path between said condenser means and said expansion valve means, said condenser being located in said path portion. 10. The refrigeration system as claimed in Claim 6, wherein said isolation valve means includes a first isolation valve in said path between said condenser means and said expansion valve means, and a second isolation valve in said path between said expansion valve means and said evaporator means. 11. The refrigeration system as claimed in Claim 6, wherein said isolation valve means includes a first isolation valve in said path between said compressor means and said condenser means, and a second isolation valve in said path between said first isolation valve and said condenser means. 12. The refrigeration system as claimed in Claim 6, wherein said isolation valve means includes a first isolation valve in said path between said compressor means and said condenser means, and a second isolation valve in ' said path between said evaporator means and said expansion valve means, said condenser means and said expansion valve means being located in said path portion. 13. The refrigeration system as claimed in Claim 6, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 14. The refrigeration system as claimed in Claim 7, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 15. The refrigeration system as claimed in Claim 8, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 16. The refrigeration system as claimed in Claim 9, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 17. The refrigeration system as claimed in Claim 10, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 18. The refrigeration system as claimed in Claim 11, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 19. The refrigeration system as claimed in Claim 12, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 20. The refrigeration system as claimed in Claim 6, comprising means for sequencing the operation of said compressor means and said isolation valve means, whereby said isolation valve means is operated to release isolated high pressure refrigerant a period of time after start-up of said compressor means. 21. The refrigeration system as claimed in Claim 6, wherein: said isolation valve means includes a first isolation valve in said path between said condenser means and said expansion valve means; said condenser means is located in said path portion; and said compressor means is arranged to pass said refrigerant only from said low pressure side to said high pressure side. 22. The refrigeration system as claimed in Claim 6, wherein: said isolation valve means includes a first isolation valve in said path between said compressor means and said condenser means; and said compressor means is arranged to pass said refrigerant only from said low pressure side to said high pressure side. 23. The refrigeration system as claimed in Claim 6, wherein: said isolation valve means includes a first isolation valve in said path between said evaporator means and said expansion valve means; and said compressor means is arranged to pass said refrigerant only from said low pressure side to said high pressure side. 24. The refrigeration system as claimed in Claim 21, wherein said path portion includes at least one reservoir means for storage of high pressure refrigerant when said compressor is turned off. 25. The refrigeration system as claimed in Claim 22, wherein said path portion includes at least one reservoir means for storage of high pressure refrigerant when said compressor is turned off. 26. The refrigeration system as claimed in Claim 23, wherein said path portion includes at least one reservoir means for storage of high pressure refrigerant when said compressor is turned off. 27. The refrigeration system as claimed in Claim 7, wherein said isolation valve means includes a first isolation valve in said path between said condenser means and said expansion valve means, and a second isolation valve in said path between said first isolation valve and said expansion valve means. 28. The refrigeration system as claimed in Claim 7, wherein said isolation valve means includes a first isolation valve in said path between said compressor means and said condenser means, and a second isolation valve in said path between said condenser means and said expansion valve means, said condenser being located in said path portion. 29. The refrigeration system as claimed in Claim 7, wherein said isolation valve means includes a first isolation valve in said path between said condenser means and said expansion valve means, and a second isolation valve in said path between said expansion valve means and said evaporator means. 30. The refrigeration system as claimed in Claim 7, wherein said isolation valve means includes a first isolation valve in said path between said compressor means and said condenser means, and a second isolation valve in said path between said first isolation valve and said condenser means. 31. The refrigeration system as claimed in Claim 7, wherein said isolation valve means includes a first isolation valve in said path between said compressor means and said condenser means, and a second isolation valve in said path between said evaporator means and said expansion valve means, said condenser means and said expansion valve means being located in said path portion. 32. The refrigeration system as claimed in Claim 27, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 33. The refrigeration system as claimed in Claim 28, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 34. The refrigeration system as claimed in Claim 29, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 35. The refrigeration system as claimed in Claim 30, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolatii ,ι valve means. 36. The refrigeration system as claimed in Claim 31, wherein said path portion includes at least one reservoir means for the storage of high pressure refrigerant when said high pressure refrigerant is isolated in said path portion by said isolation valve means. 37. The refrigeration system as claimed in Claim 7, comprising means for sequencing the operation of said compressor means and said isolation valve means, whereby said isolation valve means is operated to release isolated high pressure refrigerant a period of time after start-up of said compressor means. 38. The refrigeration system as claimed in Claim 27, wherein, when the pressure in the high pressure refrigerant path reaches a certain pressure, said isolation valve means operates to isolate high pressure refrigerant in said path portion, and said pressure relief valve means operates to pass high pressure refrigerant to said expansion valve means. STATEMENT UNDER ARTICLE19 The claim amendments have no impact on the drawings and do not go beyond the disclosure in the international application as filed.

Inventors: LAU BILLY Y, TUNG SHYH-SHYAN, LAU, BILLY, Y., TUNG, SHYH-SHYAN
Applicants: LAU BILLY Y, TUNG SHYH SHYAN, LAU, BILLY, Y., TUNG, SHYH-SHYAN
Application year: 1994
Main classification: F25B39
IPC codes: B60H1, F25B1, F25B45